1. Field of the Invention
This invention is directed toward an improved gravity cooling unit.
2. Description of Related Art Including Information Disclosed Under 37 CFR xc2xa7xc2xa71.97 and 1.98
Gravity cooling units are cooling units used to cool room air without using a fan or a blower. The cooling unit has a plurality of cooling fins mounted on lengths of pipe which pipe lengths are joined together at their ends, past the fins, in one or more serpentine coils. The coils carry refrigerant. The cooling fins form a single, slab-like structure or column that is mounted on the ceiling of the room to be cooled with a wide side of the column facing the ceiling. The column is spaced from the ceiling to form a path providing air flow to the top of the fins. A condensate pan is mounted beneath the column to collect condensate from the column. The condensate pan is spaced below the column to form a path providing air flow from the bottom of the fins. The warm air in the room rises, passes over and down through the fins of the unit to be cooled, and passes out the air path between the pan and the column back into the room. These known units are quite bulky, needing a top clearance from the ceiling for air flow and a bottom clearance for air flow between the condensate pan and the fins. They are also relatively inefficient since the condensate pan prevents the direct return of air to the room, the air instead having to pass around the condensate pan. A cooling unit having a wide column is also relatively inefficient since less air will flow to the middle of the unit. Less air flow can lead to freezing up of the middle of the unit.
To improve the efficiency of these gravity cooling units, it is known to provide a cooling unit with at least two columns arranged so as to provide a vertical air channel between the columns. Such a unit is shown in C.P. U.S. Pat. No. 1,202,957, issued Apr. 8, 1986, Guy St. Pierre, inventor. Each column has the long axis of the fins vertical. To avoid blocking the air channel a separate, generally horizontal, condensate pan is provided under each column. This arrangement provides better air flow and is therefore more efficient than those cooling units which employ a single wide column. However the arrangement still requires a top clearance from the ceiling to allow warm air to flow over the columns and down into the vertical passage. Thus the unit takes up a relatively large amount of vertical space in the room and limits head room. These cooling units are used primarily in cold rooms which are built with low ceilings to begin with and thus the vertical space that the units occupy is critical. The vertical columns are also inefficient since condensate from the top pipe lengths in the columns will drop onto the lower pipe lengths thereby lowering their cooling efficiency. Wide units also still have the problem of providing sufficient air flow to the center of the unit making the unit inefficient. Also, the relatively flat condensate pans do not drain well leaving stagnant puddles of water which can promote dangerous bacterial growth.
It is the purpose of the present invention to provide an improved gravity cooling unit which is much more efficient than the known units. It is another purpose of the present invention to provide an improved gravity cooling unit which requires less vertical space when mounted from the ceiling. It is another purpose of the present invention to provide a gravity cooling unit which handles the condensate associated with the unit more efficiently thereby minimizing the risk of bacterial growth problems.
In accordance with the present invention it has been discovered that if the column of a cooling unit is angled to the vertical, the column can be mounted almost directly against the ceiling thus reducing the vertical space required for the unit. The warm air in the room will flow up the wide side of the fin structure facing the ceiling and will fall through the fins, being cooled, to emerge from the wide side of the fin structure facing away from the ceiling. The angled position of the column enhances the flow of the air through the fins making the unit more efficient. Also, with the columns being angled, the lengths of the cooling tubes in the column are staggered horizontally and condensate does not drip from one to another thereby further increasing efficiency. Condensate collection is improved by providing a condensate collector, in the form of a condensate pan, under the column that has its bottom wall parallel to the bottom of the fins. Condensate thus flows down the bottom wall to its juncture with the an inner side wall to collect in the junction and flow toward one end of the pan. The sloping bottom wall eliminates the likelihood of stagnant areas or puddles of condensate collecting on the bottom wall. Condensate is also collected more efficiently off the fins when using an angled column. The condensate runs down the surfaces of the fin to its lower side edges, and then down the edges to drop off the lowest corner of the fins into the wall junction in the condensate pan.
A plurality of the angled columns can be mounted in parallel to form a single cooling unit. A vertical partition can separate adjacent columns. It is preferred however that the columns be arranged in pairs with the two columns in each pair angled toward each other toward the top. Each pair of columns, when viewed from the end, will form an A-frame shaped structure. The downwardly diverging space between the two columns, through which the cooled air drops, will act as a draft inducer improving the flow of air through the unit and making it still more efficient.
A baffle can be provided along the lower part of the wide side of the fin structure that faces the ceiling. The baffle prevents the rising warm air from immediately entering the fins. The warm air must rise over the baffle before entering the fins and this again induces more air flow through the fins because some of the cool air now exits substantially lower from where the warm air enters. Greater air flow improves efficiency.
Preferably a second condensate pan is provided beneath the first condensate pan on each column. The second pan carries away any condensate that may overflow the first condensate pan, collects any condensate that may form on the bottom of the first pan, and more importantly, insulates the first condensate pan from the warm air below the pans to minimize freezing. The second condensate pan is unshaped with its bottom wall generally horizontal and spaced a slight distance from the bottom wall of the first condensate pan. Preferably the outer side wall of the second condensate pan is made longer than the inner side wall of the pan. This longer, outer wall forms the baffle along the lower, outer part of the fins.
The condensate collector can also be in the form of condensate pan having a bottom wall that is hollow. The hollow structure insulates the top surface of upper wall section of the bottom wall and also serves to collect any condensation that may form on the bottom of the upper wall section of the bottom wall.
The invention is particularly directed toward a gravity cooling unit having at least one pair of cooling columns, each cooling column consisting of a plurality of spaced-apart, rectangular, parallel, cooling fins mounted on lengths of cooling pipe which lengths are joined at their ends outside the fins to form one or more serpentine cooling coils in the column. The cooling unit has mounting means for use in mounting the unit on a ceiling. The cooling columns are each fixed to the mounting means to have the longitudinal axis of the fins at a small acute angle to the vertical and a short side of the fins substantially against the ceiling when the cooling unit is mounted on the ceiling. The pair of cooling columns diverge from each other downwardly from the ceiling to form a vertical, downwardly diverging, air path between them. A condensate collector is positioned under each column, the collector extending the length of the column and at least wide enough to be located under all the pipe lengths in each column